An embodiment of the invention relates to an image processing apparatus and method.
In an image captured using a photographing device, such as a digital photographing device, a video camera, a film camera, or the like, distortion is generated due to an influence of distortion aberration characteristics of a lens. Distortion of an image is not serious when a high-performance lens is used, but it is difficult to perfectly avoid an influence of distortion of an image when a low-performance and cheap lens is used or an optical zoom lens is used. Recently, an image processing apparatus for correcting distortion of an image through signal processing has been recently proposed, for example, in the following patent documents: Japanese Patent Laid-Open Gazette No. 2008-236544 (“the '544 Patent Publication”) and Japanese Patent Laid-Open Gazette No. 2004-234379 (“the '379 Patent Publication”)
The invention disclosed in the '544 Patent Publication divides image data into rectangular data having a horizontal width corresponding to a predetermined number of pixels, determines whether an image to be corrected is convex-distorted or concave-distorted to divide the image into 4 quadrants by using a horizontal axis and a vertical axis which pass through the center, and determines to which quadrant a quadrant of a rectangle to be corrected corresponds to correct optical distortion different for each rectangle in each quadrant. The invention disclosed in the '379 Patent Publication compresses a distortion quantity necessary as a parameter during distortion correction by using an operation to reduce the size of a parameter maintaining memory.
However, the invention disclosed in the '544 Patent Publication is meaningless when the number of static random access memories (SRAMs) for distortion correction is nearly fixed, and in some correction modes, some line memories are not used. The invention disclosed in the '379 Patent Publication can reduce the circuit scale by reducing the usage of a huge-size parameter table, but some line memories are not used like in the invention disclosed in the '544 Patent Publication. Many SRAMs need to be mounted for distortion correction, but they are not mostly used for purposes other than distortion correction. Conventionally, clocks are provided to all the SRAMs, increasing power consumption.